New and better construction methods and materials for building structures such as single homes, attached homes, and other residences have resulted in more air tight construction, to the point where ventilation has become an air quality issue whereby humidity control is a necessity for both new home construction as well as major home renovation projects.
Summertime humid air infiltration into a structure can lead to mold formation resulting in structural damage and health issues. Further, increased air conditioning is required and as a result, increased energy requirements.
This movement/infiltration of air from either the outside or other areas of the structure to the basement or crawl space, where temperatures are lower, results in condensation, which can lead to mold formation and odours and resultant health issues. Structural damage in the basement/crawl space may also result.
Mold and resulting mildew conditions are considered to be health hazards and a major contributor to asthmatic conditions, especially in children.
A negative air pressure can occur in the basement/crawl space of a home as a result of the new and better construction methods and ventilation devices. When a negative air pressure exists, outside air and other gases are drawn into the basement/crawl space and have a negative impact on the structure of the home and the occupants thereof. Current house ventilation systems do not address the issues of negative air pressure and their impact on basement/crawl space humidity and condensation, during periods of high temperatures and humidity.
Temperature and humidity levels of supply air during periods of high or extreme heat, humidity or cold, delivered by current house ventilation systems, are such that significant energy expenditures are needed to maintain comfort levels.
There are a number of basement or crawlspace systems commercially available that attempt to address the basement and/or crawlspace humidity and condensation problem. However, they are ineffective during prolonged summertime periods with high temperature and humidity. Additionally, these systems add a considerable load to the energy requirements for air conditioning.
Current commercially available basement and crawlspace systems do not meet the requirements for all North American climates (coastal, southern, northern, etc.) as well as the building codes in these different jurisdictions.
De-humidifiers address localized indoor humidity problems, however, they are very costly to operate and do not address indoor air quality. Heat recovery ventilators (HRV) and energy recovery ventilators (ERV) are likewise costly to operate from a strictly operating point.
In order to reduce costs to the end user, reduce energy demand from utilities and reduce CO2 emissions on a greater scale, energy savings must be promoted.
There is therefore a need for a ventilation system which controls humidity, reduces costs of air-conditioning during the summertime and increases humidity control efficiency during continuous hot and humid days.